Imperial German cavalry officer Paul Grünert served as Eighth Army Senior Quartermaster
under General von Hindenburg during the 1914 Battle of Tannenberg.
He served the remainder of the war years as an field army chief of staff
and a divisional commander. General Grünert
additionally spent the final few months of the Great War in command of
reserve corps troops.

It was General Grünert
who, along with his subordinate Max Hoffmann, tried to convince Eighth
Army Commander von Prittwitz to move the bulk of his forces south in
order to bolster German defensive action against Russian General Samsonov. The two
German general staffers were counting on the fact that Rennenkampf, to be held
by a skeleton German force, would not pursue southward to assist
Samsonov. This plan was in fact executed immediately after Prittwitz had
been replaced by Hindenburg, leading to the remarkable German victory at
Tannenberg.Grünert
mainly functioned as Hindenburg's top communications officer during this
engagement.

General Grünert switched
in November to working as Mackensen's Chief of Staff in the newly-formed
Ninth Army as they pushed southward into Poland to conduct operations
there. In this context, Mackensen and his deputy Grünert
enjoyed Hindenburg's and Ludendorff's
compete confidence and trust. Grünert
continued in the same capacity under
Prince Leopold von Bayern as his troops marched into Warsaw in the
summer of 1915. For his efforts, the Kaiser
presented himwith Germany's Order
of the Red Eagle, 2nd Class, with oak leaves and swords.

Following some deserved home leave for Christmas, Grünert
was transferred in January 1916 to the
Argonne Forest on the Western Front, where he took command of 25th
Reserve Infantry Division. He was soon switched to the River Somme
area, however, where he took the post as Fritz von Below's Chief of
Staff. In July, he again went East to take charge of first the 3rd
Division, then 119th Division, which was engaged in western Ukraine. The
119th was ordered in May 1917 to join with Fourth Army forces at
Flanders on the Western Front. In March 1918, Generalleutnant Grünert
relieved Hermann von Staabs as commander
of XXXIX. Reserve Corps. It was in this capacity that he proved himself
worthy of the Kaiser's awarding him with the Pour le Merite.

Toward the end of the summer 1918, Grünert
was put in command of XXXX. Reserve Corps,
forming the left wing of Germany's Sixth Army which was entrenched near
Lens. These troops gradually withdrew to the Antwerp-Maas Line until the
cease of hostilities. It fell upon Commander Grünert
to lead them back to the homeland for the
demobilization process.